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    <script>
        var arr = ['a', 'b', 'c', 'd', 'e'];
        var rel = arr.map(function(value, index, array) {
            console.log(value);
            console.log(index);
            console.log(array);
            // 需要return结果通过操作的返回值进行接受
            // map返回一个新数组，数组中的元素为原始数组元素调用函数处理后的值
            // return value + '操作后';
            return '认真听';
        });
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